How do you identify whether the components are in parallel or series?

[kenhung123]

How would I know how to add the resistance? All i know is the 40kohm is in series...

[TrueTears]

maybe the 40 and 30 kohm are in parallel and then the 16 and 30 kohm is in parallel and then the 5 kohm is in series with them all, just my guess.

[/0]

Why are there resistors at junctions? They shouldn't be there.

[kenhung123]

Hmm, well, I actually tried to simplify the original circuit. I must have done it wrong. The original is actually

[Mao]

10k is parallel with 30k [on the right], simplify to give you R1

R1 is in series with 5k, simplify to give you R2

R2 is parallel to 30k, simplify to give you R3

R3 is in series with 40k, simplify to give R_eff

As a general rule, trace the current flow. Parallel components start at the same point, end at the same point. Series components join head-to-toe.